As computational demands increase, there is a growing need for a large number, i.e., greater than 600, of electrical signal connections for removable printed circuit boards. Typically, removable printed circuit boards are inserted into a card cage or expansion slot of a computer. Often, these printed circuit boards, or daughter cards, are connected to the motherboard of a computer through the backplane of the card cage. Electrical circuitry on the circuit boards connects to the backplane by any of several types of known connectors and terminals. The circuit boards are thereby interconnected by the backplane to circuitry of other circuit boards in the array of slots and/or to other circuitry within the computer. The circuit boards are, therefore, limited by the number of electrical connections available on the backplane.
For example, printed circuit boards of the Eurocard 9U by 400 mm format have three 96 pin DIN connectors along their back edge. Most of these connections are dedicated to VME signal lines and power supplies. Thus, at most, approximately 100 connections are available for non-standard power supplies and signal connections. The complexity of today's computers demand more connections to exchange power and electrical signals.
One solution is to add connections to the front of the circuit board. Adding connections to the front edge of the circuit board is possible; however, it is not practical for large systems. The associated cabling would make circuit board removal and replacement very difficult.
An example of a high density printed circuit board card connection system is described in Baumbaugh U.S. Pat. No. 5,626,480. The '480 patent describes a zero insertion/extraction force printed circuit board card connection system which includes a cam-operated locking mechanism disposed along an edge portion of the printed circuit board.
The present printed circuit board connection system addresses the need for increased signal connections with a simple mechanical arrangement that includes a wedge-operated connector along an edge portion of a printed circuit board.
It is therefore an object of the present invention to provide a card connection system having 1000 or more electrical signal connections disposed along an edge of a printed circuit board other than the back edge.
Another object of the present invention is to provide electrical connections that are able to be mated after insertion, yet separable during circuit board insertion and extraction.
A further object of the present invention is to provide a card connection system which provides adequate ventilation when a plurality of circuit boards including the present connection system are installed as an array within a card cage.